The Electron Microscopy Unit is equipped with a transmission (TEM) and scanning (SEM) electron microscopes that can be used in a wide range of applications for analysis of biological, medical, environmental and material samples. These analyses include;

1. Ultrastructural analysis using TEM
2. Three dimensional (3D) tomography of partials using Tomograph-TEM system
3. Topographical analysis using SEM
4. Elemental Analysis using EDS system

Applications:

The Electron Microscopes are scientific equipment used for research, teaching, training, industry and consultancy in biological, environmental and material science applications. These instruments are capable of simplifying atomic level structural analyses in biological and materials sciences as well as the semiconductor and pharmaceutical industries.

1.  Life Sciences:

• Allow understanding of cells, proteins, DNA, and drug interactions.
• Allow researchers to directly visualize cellular structures, viruses and individual proteins.
• Investigate the surface topography of cells and isolated macromolecules, and provide insight into the dynamics of living proteins at sub-nanometer resolution.
• Used as a diagnostic tool in hospital pathology labs.
• Used as investigative tool in forensic science.
• Provide high resolution, three-dimensional images of structural details.

2.  Materials Science Applications:

• Allow understanding of materials structure and properties, and the bonding between atoms.
• Used in the characterization of materials.
• Study variations in specimen temperature and ambient gas pressure and specimen straining.
• Hard, soft, frozen, and composite materials can easily be examined.

3.  Nanotechnology Applications:

Multidisciplinary field, which covers a vast and diverse array of devices derived from engineering, biology, physics and chemistry. These devices include nanovectors for the targeted delivery of anticancer drugs and imaging contrast agents. Nanowires and nanocantilever arrays are among the leading approaches under development for the early detection of precancerous and malignant lesions from biological fluids. These and other nanodevices can provide essential breakthroughs in the fight against cancer.

  A.  Nanomaterial Applications:

• Used in all areas of biological and biomedical investigations because of its ability to view the finest cell structures.
• Used as a diagnostic tool in hospital labs.

  B.  Life Science Applications:

• Observe 3-D protein structures.
• Internal structures of cells.
• 3-D reconstruction of  virus particles. 

  C.  Semiconductor & IT Applications:

• Particle analysis.
• Surface analysis.

  D.  Environmental Applications:

• Analysis of dusts and catalysts.
• Analysis of corrosive materials.
• Analysis of contaminants.

4.  Semiconductor Applications:

• Semiconductor fabrication.

5.  Quality Control:

• Useful in pharmaceutical industry to detect contaminants such as natural and synthetic fibers prior to commercially produced. Microscopically examination coupled with sample isolation, preparation, and analytical methods optimized for small particles, used to identify contaminations.

6.  Scientific / Academic Research:

• Useful in molecular and structural biology research to helps study proteins and genetic material. Immunogold labeling technique is used to localize proteins within cells and organelles.
• Powerful tool in the structural investigation of large biological complexes. Techniuqe involves Reconstruction of Macromolecular Complexes (using Electron Tomography).

Equipment:

Transmission Electron Microscope (TEM)

The JEOL JEM-1400 TEM is an ultra-high magnification instrument offering state-of-the-art high contrast imaging up to x1,200,000 magnification with a high resolution of up to 0.2 nm for observing the internal structure (ultrastructure) of a specimen in micrometer (µm) and nanometer (nm) ranges.   The system has the capability of exporting data to a dedicated tomography system for 3D structural elucidation.  The specimen chamber has the capacity to load five samples at a time, 1mm³ biological samples are sliced into ultrathin sections from 60-90nm thickness using an ultramicrotome and then loaded onto Formvar carbon coated grids.

The TEM uses an electron beam instead of light to study objects at high resolution. The electron beam is transmitted and focused through the sample section to create a 2D image in grey scale.

The process of sample preparation is dependent on the sample type.  Biological samples are first fixed to ensure there is no degradation using an automated tissue processor from RMC (EMP -5160), embedded in Araldite epoxy resin, and then sectioned using a RMS Power Tome Ultracutmicrotome XL to produce ultra-thin sections from 60-90nm if required.  Inorganic geological samples do not require fixing however they still need to be prepared and then mounted on the Formvar carbon coated grids.

JEOL JEM-1400 TEM with 3D Tomography System

JEOL JSM-6510LA SEM with SED, BSD, and EDS detectors

The JEOL JSM-6510LA SEM is capable of high magnification for observing the surface structure (topography) of a specimen in micrometer (µm) and nanometer (nm) ranges.  The magnification is variable from x10 to x300,000 with a resolution of up to 3 nm. Unlike conventional light microscopes the SEM uses a beam of electrons to scan the sample; the reflected electrons are then detected using different types of detectors to create a 3D image in grey scale.

The Preparation of sample depends on the sample type.  The microscope operates at two modes; a high vacuum mode for which a treated sample must be used; and low vacuum mode where untreated sample can be used. Biological samples are fixed with Kamovsky's fixative to ensure there is no degradation, dehydrated in ethanol followed by Critical Point Drying using an autosamdri-815.   The specimens are then mounted on stubs using carbon adhesive tape; finally they are Sputter coated with platinum particles using a JEOL JFC-1600 coater. Inorganic geological samples do not require fixing and dehydration however they still require coating with platinum to aid conductivity.

The sample is then loaded into the sample stage and screened by using different detectors according to the requirements.  Secondary electron detector (SED) produce topography imaging, Backscattered electron detector (BSD) produce sample compositional imaging.  The X-Ray detector (EDS) is used for both qualitative and semi quantitative elemental analysis of the specimen, an image can also be generated showing the distribution of the elements within the sample topography.

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Electron Microscopy Request Form